Zen

Zen is not his real name as he is part of a type of demon lineage that cannot give out their "true" names unless if it's their eternal partner. Which type of demon is he is something he will never say, not even to his closest friend. Many said that he wraps his mouth up in order to remind himself to keep his secrets to himself whereas others speculate that he does this to suppress his demon powers/ instincts. Even though he doesn't speak much at all, you can often know what his is thinking by looking at his facial expression.